**5.4 Odorization and deodorization**

142 Biogas

In reality the gas networks are operated and surveyed by control systems (SCADA) consisting of a control center and remote control stations including remote control and data transmission. In general, a lot of data is acquired transmitted and stored but there is not

Intermediate points in the network are sparsely equipped or positioned, strongly depending on operational needs. Transport networks have a more detailed data view than distribution

Consumer data, especially small "home" consumers, are read once a year, only. When executing computations with small consumers their hourly values are deduced from yearly readings using standardized methods (standard load profiles, SLP). In all computations – when SLP's are involved – it must be kept in mind that this method influences the accuracy of the computing results when a short time period is considered. Opposite to the former small consumers the big consumers are measured and registered continuously; so

**4.3 Consumer data (home, standard load profiles; Continuous registration)** 

Network operators favor smooth operating conditions for a number of reasons:

• Avoid sudden pressure changes (could generate shock waves, higher gas velocity) • Avoid bigger and many flow changes (leads to pressure changes , regulator instability

• Deliver/provide constant gas quality (i.e. colorific value), (operate within allowed

In reality more or less big changes are likely to occur each hour (minute) due to changes of the consumption, scheduled feed-in according to delivery contracts, natural variation of gas

In wintertime gas consumption is high and normally biogas is a smaller amount of the total consumption causing normally no transportation problems. But in summertime when the gas consumption is very low some areas face the situation that biogas production is higher than the total consumption in a distribution (sub-) network. In effect, biogas floods the network but could not be consumed, even if the regulating devices would have been changed to different settings to retain natural gas flow. So the exceeding or all biogas must be transported to other

areas via additional pipes which have to be provided by the network operator.

**4.2 Control system, full and sparse measurement coverage** 

• Input points: flow, pressure, gas quality

networks.

**5. Operational aspects 5.1 Smooth operation goal** 

and wear out)

**5.2 Local biogas flooding** 

quality of gas sources/production fields.

limits).

• Intermediate points: flow, pressure (sparsely)

always a full coverage for each point in the network. One can rely on:

• Output points: flow of consumers (registered continuously)

computations can be made very accurate even in short periods.

If biogas is fed into a distribution network it must be odorized before. Odorization adds the typical alarming and disgusting smell to the gas that warns human beings in case of leakage. If in the situation that excess biogas exists in a network area odorized biogas must be deodorized before entering the transportation network that has no odorized gas (odorization will be added downstream at the distribution level, only).
